/*
 * Copyright (C) 2009 The Android Open Source Project
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the
 * License. You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS"
 * BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */

package com.badlogic.gdx.backends.android.livewallpaper.surfaceview;

/*
 * Copyright (C) 2008 The Android Open Source Project
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the
 * License. You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS"
 * BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */

import javax.microedition.khronos.egl.EGL10;
import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.egl.EGLContext;
import javax.microedition.khronos.egl.EGLDisplay;

import android.graphics.PixelFormat;
import android.opengl.GLSurfaceView;
import android.service.wallpaper.WallpaperService.Engine;
import android.util.Log;

import com.badlogic.gdx.backends.android.surfaceview.ResolutionStrategy;

/**
 * A simple GLSurfaceView sub-class that demonstrate how to perform OpenGL ES 2.0 rendering into a GL Surface. Note the following
 * important details:
 * <p/>
 * - The class must use a custom context factory to enable 2.0 rendering. See ContextFactory class definition below.
 * <p/>
 * - The class must use a custom EGLConfigChooser to be able to select an EGLConfig that supports 2.0. This is done by providing a
 * config specification to eglChooseConfig() that has the attribute EGL10.ELG_RENDERABLE_TYPE containing the EGL_OPENGL_ES2_BIT
 * flag set. See ConfigChooser class definition below.
 * <p/>
 * - The class must select the surface's format, then choose an EGLConfig that matches it exactly (with regards to
 * red/green/blue/alpha channels bit depths). Failure to do so would result in an EGL_BAD_MATCH error.
 */
public class GLSurfaceView20 extends DefaultGLSurfaceView {
    static String TAG = "GL2JNIView";
    private static final boolean DEBUG = false;

    final ResolutionStrategy resolutionStrategy;
  
    public GLSurfaceView20(Engine engine, ResolutionStrategy resolutionStrategy) {
        super(engine, resolutionStrategy);
        this.resolutionStrategy = resolutionStrategy;
        init(false, 16, 0);
    }

    public GLSurfaceView20(Engine engine, boolean translucent, int depth, int stencil, ResolutionStrategy resolutionStrategy) {
        super(engine, resolutionStrategy);
        this.resolutionStrategy = resolutionStrategy;
        init(translucent, depth, stencil);

    }

    private void init(boolean translucent, int depth, int stencil) {

        /*
           * By default, GLSurfaceView() creates a RGB_565 opaque surface. If we want a translucent one, we should change the
           * surface's format here, using PixelFormat.TRANSLUCENT for GL Surfaces is interpreted as any 32-bit surface with alpha by
           * SurfaceFlinger.
           */
        if (translucent) {
            this.getHolder().setFormat(PixelFormat.TRANSLUCENT);
        }

        /*
           * Setup the context factory for 2.0 rendering. See ContextFactory class definition below
           */
        
        setEGLContextFactory(new ContextFactory());

        /*
           * We need to choose an EGLConfig that matches the format of our surface exactly. This is going to be done in our custom
           * config chooser. See ConfigChooser class definition below.
           */
        setEGLConfigChooser(translucent ? new ConfigChooser(8, 8, 8, 8, depth, stencil) : new ConfigChooser(5, 6, 5, 0, depth,
                stencil));

        /* Set the renderer responsible for frame rendering */
    }


    

	static class ContextFactory implements EGLContextFactory {
        private static int EGL_CONTEXT_CLIENT_VERSION = 0x3098;

        public EGLContext createContext(EGL10 egl, EGLDisplay display, EGLConfig eglConfig) {
            Log.w(TAG, "creating OpenGL ES 2.0 context");
            checkEglError("Before eglCreateContext", egl);
            int[] attrib_list = {EGL_CONTEXT_CLIENT_VERSION, 2, EGL10.EGL_NONE};
            EGLContext context = egl.eglCreateContext(display, eglConfig, EGL10.EGL_NO_CONTEXT, attrib_list);
            checkEglError("After eglCreateContext", egl);
            return context;
        }

        public void destroyContext(EGL10 egl, EGLDisplay display, EGLContext context) {
            egl.eglDestroyContext(display, context);
        }
       		
    }

    static void checkEglError(String prompt, EGL10 egl) {
        int error;
        while ((error = egl.eglGetError()) != EGL10.EGL_SUCCESS) {
            Log.e(TAG, String.format("%s: EGL error: 0x%x", prompt, error));
        }
    }

    private static class ConfigChooser implements GLSurfaceView.EGLConfigChooser {

        public ConfigChooser(int r, int g, int b, int a, int depth, int stencil) {
            mRedSize = r;
            mGreenSize = g;
            mBlueSize = b;
            mAlphaSize = a;
            mDepthSize = depth;
            mStencilSize = stencil;
        }

        /*
           * This EGL config specification is used to specify 2.0 rendering. We use a minimum size of 4 bits for red/green/blue, but
           * will perform actual matching in chooseConfig() below.
           */
        private static int EGL_OPENGL_ES2_BIT = 4;
        private static int[] s_configAttribs2 = {EGL10.EGL_RED_SIZE, 4, EGL10.EGL_GREEN_SIZE, 4, EGL10.EGL_BLUE_SIZE, 4,
                EGL10.EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT, EGL10.EGL_NONE};

        public EGLConfig chooseConfig(EGL10 egl, EGLDisplay display) {

            /*
                * Get the number of minimally matching EGL configurations
                */
            int[] num_config = new int[1];
            egl.eglChooseConfig(display, s_configAttribs2, null, 0, num_config);

            int numConfigs = num_config[0];

            if (numConfigs <= 0) {
                throw new IllegalArgumentException("No configs match configSpec");
            }

            /*
                * Allocate then read the array of minimally matching EGL configs
                */
            EGLConfig[] configs = new EGLConfig[numConfigs];
            egl.eglChooseConfig(display, s_configAttribs2, configs, numConfigs, num_config);

            if (DEBUG) {
                printConfigs(egl, display, configs);
            }
            /*
                * Now return the "best" one
                */
            return chooseConfig(egl, display, configs);
        }

        public EGLConfig chooseConfig(EGL10 egl, EGLDisplay display, EGLConfig[] configs) {
            for (EGLConfig config : configs) {
                int d = findConfigAttrib(egl, display, config, EGL10.EGL_DEPTH_SIZE, 0);
                int s = findConfigAttrib(egl, display, config, EGL10.EGL_STENCIL_SIZE, 0);

                // We need at least mDepthSize and mStencilSize bits
                if (d < mDepthSize || s < mStencilSize) continue;

                // We want an *exact* match for red/green/blue/alpha
                int r = findConfigAttrib(egl, display, config, EGL10.EGL_RED_SIZE, 0);
                int g = findConfigAttrib(egl, display, config, EGL10.EGL_GREEN_SIZE, 0);
                int b = findConfigAttrib(egl, display, config, EGL10.EGL_BLUE_SIZE, 0);
                int a = findConfigAttrib(egl, display, config, EGL10.EGL_ALPHA_SIZE, 0);

                if (r == mRedSize && g == mGreenSize && b == mBlueSize && a == mAlphaSize) return config;
            }
            return null;
        }

        private int findConfigAttrib(EGL10 egl, EGLDisplay display, EGLConfig config, int attribute, int defaultValue) {

            if (egl.eglGetConfigAttrib(display, config, attribute, mValue)) {
                return mValue[0];
            }
            return defaultValue;
        }

        private void printConfigs(EGL10 egl, EGLDisplay display, EGLConfig[] configs) {
            int numConfigs = configs.length;
            Log.w(TAG, String.format("%d configurations", numConfigs));
            for (int i = 0; i < numConfigs; i++) {
                Log.w(TAG, String.format("Configuration %d:\n", i));
                printConfig(egl, display, configs[i]);
            }
        }

        private void printConfig(EGL10 egl, EGLDisplay display, EGLConfig config) {
            int[] attributes = {EGL10.EGL_BUFFER_SIZE, EGL10.EGL_ALPHA_SIZE, EGL10.EGL_BLUE_SIZE, EGL10.EGL_GREEN_SIZE,
                    EGL10.EGL_RED_SIZE, EGL10.EGL_DEPTH_SIZE, EGL10.EGL_STENCIL_SIZE, EGL10.EGL_CONFIG_CAVEAT, EGL10.EGL_CONFIG_ID,
                    EGL10.EGL_LEVEL, EGL10.EGL_MAX_PBUFFER_HEIGHT, EGL10.EGL_MAX_PBUFFER_PIXELS, EGL10.EGL_MAX_PBUFFER_WIDTH,
                    EGL10.EGL_NATIVE_RENDERABLE, EGL10.EGL_NATIVE_VISUAL_ID, EGL10.EGL_NATIVE_VISUAL_TYPE,
                    0x3030, // EGL10.EGL_PRESERVED_RESOURCES,
                    EGL10.EGL_SAMPLES, EGL10.EGL_SAMPLE_BUFFERS, EGL10.EGL_SURFACE_TYPE, EGL10.EGL_TRANSPARENT_TYPE,
                    EGL10.EGL_TRANSPARENT_RED_VALUE, EGL10.EGL_TRANSPARENT_GREEN_VALUE, EGL10.EGL_TRANSPARENT_BLUE_VALUE, 0x3039, // EGL10.EGL_BIND_TO_TEXTURE_RGB,
                    0x303A, // EGL10.EGL_BIND_TO_TEXTURE_RGBA,
                    0x303B, // EGL10.EGL_MIN_SWAP_INTERVAL,
                    0x303C, // EGL10.EGL_MAX_SWAP_INTERVAL,
                    EGL10.EGL_LUMINANCE_SIZE, EGL10.EGL_ALPHA_MASK_SIZE, EGL10.EGL_COLOR_BUFFER_TYPE, EGL10.EGL_RENDERABLE_TYPE, 0x3042 // EGL10.EGL_CONFORMANT
            };
            String[] names = {"EGL_BUFFER_SIZE", "EGL_ALPHA_SIZE", "EGL_BLUE_SIZE", "EGL_GREEN_SIZE", "EGL_RED_SIZE",
                    "EGL_DEPTH_SIZE", "EGL_STENCIL_SIZE", "EGL_CONFIG_CAVEAT", "EGL_CONFIG_ID", "EGL_LEVEL", "EGL_MAX_PBUFFER_HEIGHT",
                    "EGL_MAX_PBUFFER_PIXELS", "EGL_MAX_PBUFFER_WIDTH", "EGL_NATIVE_RENDERABLE", "EGL_NATIVE_VISUAL_ID",
                    "EGL_NATIVE_VISUAL_TYPE", "EGL_PRESERVED_RESOURCES", "EGL_SAMPLES", "EGL_SAMPLE_BUFFERS", "EGL_SURFACE_TYPE",
                    "EGL_TRANSPARENT_TYPE", "EGL_TRANSPARENT_RED_VALUE", "EGL_TRANSPARENT_GREEN_VALUE", "EGL_TRANSPARENT_BLUE_VALUE",
                    "EGL_BIND_TO_TEXTURE_RGB", "EGL_BIND_TO_TEXTURE_RGBA", "EGL_MIN_SWAP_INTERVAL", "EGL_MAX_SWAP_INTERVAL",
                    "EGL_LUMINANCE_SIZE", "EGL_ALPHA_MASK_SIZE", "EGL_COLOR_BUFFER_TYPE", "EGL_RENDERABLE_TYPE", "EGL_CONFORMANT"};
            int[] value = new int[1];
            for (int i = 0; i < attributes.length; i++) {
                int attribute = attributes[i];
                String name = names[i];
                if (egl.eglGetConfigAttrib(display, config, attribute, value)) {
                    Log.w(TAG, String.format("  %s: %d\n", name, value[0]));
                } else {
                    // Log.w(TAG, String.format("  %s: failed\n", name));
                    while (egl.eglGetError() != EGL10.EGL_SUCCESS)
                        ;
                }
            }
        }

        // Subclasses can adjust these values:
        protected int mRedSize;
        protected int mGreenSize;
        protected int mBlueSize;
        protected int mAlphaSize;
        protected int mDepthSize;
        protected int mStencilSize;
        private int[] mValue = new int[1];
    }
}
